Acyanotic congenital heart disease

Question 1

List the L-R shunts

Answer 1

Atrial Septal defects
Ventricular Septal defects
Patent Ductus Arteriosus
Endocardial cushion defects
Partial anomalous pulmonary venous drainage

Question 2

What happens in L-R shunts

Answer 2

Characterized by hyper-oxygenated blood which keeps re-circulating through the lungs –at expense of systemic circulation.

The lungs become over-perfused because they receive:
all the deoxygenated blood from the systemic venous return
PLUS blood shunted from the left side

Volume overload of one or more cardiac chambers

Increased cardiac workload to supply rest of body with enough blood to meet metabolic demands

Question 3

What is the relation of pulmonary to systemic blood flow and how does this affect the severity of L-R shunts

Answer 3

this is 1:1 because equal volume of blood is pumped to body and lungs

In L-R shunts, this ratio is >1
Qp:Qs ratio <1.5:1 = small shunt;
1.5-2.0:1 = moderate,
while >2:1 is a large shunt

Question 4

Describe the levels of L-R shunting

Answer 4

Venous level: anomalous drainage of pulmonary veins( total, partial) – into RA and /or its tributaries

Atrial level: atrial septal defects / single atrium

Ventricular level: ventricular septal defects / single ventricle

Arterial level: PDA, arteriovenous malformations

Question 5

What are the types of ASD

Answer 5

Ostium secundum
Ostium primum
Sinus venosus
Coronary sinus

Question 6

What causes ostium secundum defects

Answer 6

Excessive fenestration or resorption of septum primum
Under development of septum secundum
Or combination of both

Question 7

The magnitude of ASD depends on what factors

Answer 7

Size of the defect

Relative compliance of the right and left ventricles

Vascular resistance in the pulmonary and systemic circulations

Question 8

Clinical features of ASD

Answer 8

Asymptomatic

Mild FTT in younger children

Varying degrees of excercise intolerance seen in older children

Question 9

What investigations would you carry out for ASD and what will be the findings

Answer 9

CHEST XRAY
Normal heart size in small defects

In large defects:
Cardiomegaly
Enlarged RA and RV
Increased pulmonary vascular markings

ECG
Right axis deviation
Right ventricular hypertrophy

ECHO
Location and size of defect
Right atrial and right ventricular enlargement

Question 10

Describe the natural history of ASD

Answer 10

Most children with ASD remain asymptomatic

The defect may decrease in size with up ato 33% closing spontaneously usually before age 30 months, especially if small

Spontaneous closure is rare after age 4 years

Symptoms such as pulmonary hypertension, congestive heart failure and complications such as atrial arrthymias usually develops in adults especially with large ASDs.

Question 11

What is the most common cardiac malformation

Answer 11

VSD accounting for 25% of all CHD

Question 12

What are the types of VSD

Answer 12

Perimembranous

Muscular (or Trabecular)

Inlet (or Posterior / AVcanal-type / endocardial cushion–type)

Outlet (or Subarterial /supracristal / infundibular, subpulmonic )

Question 13

Describe the pathophysiology of VSD

Answer 13

When both ventricles simultaneous contract, blood shunts from the left to the right side of the heart.

The shunted blood DOES NOT remain in RV but immediately enters the main pulmonary artery which dilates.

There is increased pulmonary blood flow and increased pulmonary venous return to LA

There is dilation of the LA and LV followed by LVH

The increased pulmonary venous return leads to an increase in the pulmonary arterial, arteriolar and capillary pressure leading to increased pulmonary interstitial fluid

When severe, pulmonary edema results

Prolonged exposure of pulmonary vascular bed to higher than normal blood flow at high pressure results in Pulmonary vasoconstriction in an attempt to protect the lungs

This increases pulmonary vascular resistance(PVR) and subsequently causes pulmonary hypertension(PHT)
The PHT is initially reversible but ultimately irreversible changes occur in the smooth muscle which lead to pulmonary vascular disease

Question 14

Describe eisenmenger physiology

Answer 14

If this pulmonary vascular resistance continues, the ratio of pulmonary to systemic resistance approaches 1.

Then, the shunt is no longer Left –to- right but becomes bidirectional

The patient becomes cyanotic———- Eisenmenger physiology

Question 15

Clinical presentation of VSD

Answer 15

Small Defects

Mild or no symptoms
Most often brought to the cardiologist’s attention because of a murmur (pan-systolic murmur heard best at the lower left sternal border± thrill) detectedduring routine examination.
Feeding or weight gain usually not affected.

Moderate to large defects

Delayed growth and development
Decreased exercise intolerance- feeding difficulties
Repeated pulmonary infections due to pulmonary congestion.
Excessive sweating due to increased sympathetic tone
Congestive cardiac failure
Cyanosis in older children with long standing pulmonary hypertension

Question 16

What are the physical findings of VSD

Answer 16

Pan-systolic murmur LLSB

Precordium is hyperactive with signs of congestive cardiac failure- tachypnea, tachycardia, enlarged liver(if VSD is large)

P2 is normal or slightly accentuated if there is associated pulmonary hypertension

Question 17

What investigations would you carry out for VSD and what will be the findings

Answer 17

Chest Xray

Normal heart size or minimal cardiomegaly : Small VSD

Gross cardiomegaly with increased pulmonary vascular markings: Large VSD

ECG

Normal/left ventricular hypertrophy: small VSD

Biventricular hypertrophy: Large VSD

ECHO
Position and size of the defect

CARDIAC CATHETERIZATION
Increased oxygen content and pressure in the right ventricle in large defects

Question 18

Describe the natural history of VSD

Answer 18

Ranges from spontaneous closure to congestive heart failure (CHF) to death in early infancy

30-50% of small defects close spontaneously. Spontaneous closure is frequent before the age of 2 years, uncommon after age 4 years

Most frequently observed in muscular defects (80%), then perimembranous (35-40%)

Most children with small defects remain asymptomatic but have a high risk of infective endocarditis

Large defects may get smaller but it is less common for them to close spontaneously.

These patients have repeated chest infections and heart failure despite optimal medical management

Pulmonary vascular obstructive disease can develop in patients with large defects as early as 6 -12 months of age.

Question 19

How would you treat VSD

Answer 19

Control of Congestive cardiac failure
Prompt treatment of chest infections
Palliation if definitive treatment is not immediately feasible e.g., PA banding for large VSD
Prevention of infective endocarditis
Management of complications (if present)
Surgery

Question 20

PDA is associated with which syndrome

Answer 20

Congenital rubella syndrome

Question 21

What featured differenciate PDA from VSD

Answer 21

Bounding peripheral pulses

continuous murmur at the infraclavicular area

Question 22

What is the treatment of PDA in preterms

Answer 22

If small and asymptomatic, monitor for 6 months because of the possibility of spontaneous closure

If symptomatic, medical or surgical intervention:

Fluid restriction to 120mls/kg/day
Diuretic- Furosemide 1mg/kg/dose 8-12hourly for 24-48 hours
IV Indomethacin 0.2mg/kg/dose 12 hourly for up to 3 doses ( a second course may be necessary to achieve closure in some cases) CI: Low platelet count(<80,000/mm3), bleeding tendencies, NEC, hyperbilirubinaemia, high BUN (>25mg/dl), high creatinine (>1.8mg/dl)
IV Ibuprofen 10mg/kg stat, followed 24 hours later by 5mg/kg daily x 2 doses from the 3rd day of life

Surgical ligation of the ductus when medical treatment is unsuccessful or contraindiacted

Question 23

Describe coarctation of the aorta

Answer 23

The discrete constriction/ stenosis of the upper thoracic aorta or a long segment

Rarely abdominal aorta is involved
Male dominance M:F = 2: 1
It could be familial, among patients with Turner’s syndrome

Other associated cardiac defects: abnormal aortic and mitral valve, VSD, aortic hypoplasia

Question 24

What are the types of coarctation of the aorta

Answer 24

Preductal
Juxtaductal
The usual site
Postductal

Question 25

What are the clinical features of CoA

Answer 25

NEONATAL
Feeding difficulties
Respiratory distress
Signs of shock-oliguria, severe acidaemia
Sweating
GENERAL
Radiofemoral delay
BP differential in 4 point BP determination
Single loud S2

POST NEONATAL
Upper limb hypertension
Headaches
LV failure
Tachycardia, tachypnoea
Tender hepatomegaly etc

Lower limb hypotension
Calf pain
Intermittent claudication
Poor pulses

Question 26

What investigations would you carry out to diagnose CoA and what will be your findings

Answer 26

CXR
Cardiomegaly and pulmonary congestion in severe cases

3 sign
Enlarged ascending aorta
Indentation of the COA
Post stenotic dilatation

Rib notching

ECHO

Identify segment of coarctation

Cardiac catheterization & Aortic angiography
To identify collateral blood flow and other anomalies

Question 27

How would you treat CoA

Answer 27

MEDICAL

Treat CCF, shock, acidosis
Infuse prostaglandin E1 to keep the ductus patent
Catheter intervention
Balloon dilatation and stents

SURGICAL

Resection and end-to-end anastomosis
Patch aortoplasty